1. Field of the Invention
This invention relates to subsea monitoring systems, in general, and systems and methods of visually indicating an engagement status of a submerged subsea connector which utilize voltage from the cathodic protection system for submerged subsea equipment as a power supply and/or voltage multiplier for a subsea position monitoring system, in particular.
2. Description of the Related Art
Subsea connectors can be utilized to provide upper section emergency disconnect package (“EDP”) to lower EDP section connections, blowout preventer (“BOP”) stack to wellhead connections, lower marine riser package (“LMRP”) to BOP stack connections, completion tree to wellhead connections, TPL/subsea template tiebacks, production riser assembly to subsea manifold connections, single point mooring to anchor base, and caisson completions and artificial island.
Various types of these connectors provide excellent bending in tensile load capabilities, field-proven hydraulically operated engagement, and metal-to-metal sealing. According to an emergency disconnect package implementation, the hydraulic actuators, often referred to as dogs, are typically located well within the frame structure of the emergency disconnect package, making visual verification of complete engagement generally impossible.
A standard technique for reducing corrosion of the metal items and surfaces of the EDP after deployment underwater equipment, which are prone to corrosion due to the electrolytic nature of the surrounding seawater, is to use cathodic protection (“CP”). A widely-used form of CP is the galvanic anode-type cathodic protection, in which a sacrificial metal surface is positioned proximate to the metal items to be protected. The sacrificial metal material is chosen which has a greater magnitude electrochemical potential than the item to be protected. Commonly used sacrificial metal materials include, for example, alloys of zinc, magnesium, and aluminum. When located subsea adjacent the metal components and surfaces to be protected, for example, the sacrificial metal material will be corroded instead of to the item being protected. Eventually, the sacrificial material will be corroded to such an extent that replacement of the sacrificial material is necessary.